Art of manufacturing square-bottom paper bags.



Patented Feb. l9, 19m.

.w. A;. LORENZ. ART OF MANUFACTURING SQUARE BOTTDM PAPER BAGS.

(Application filed June 19, 1.900.)

. (No Modal.)

In ven tor.

No. 668,|98. Pateht'ed Fe'h. l9, I901.

w. A. LORENZ ART'EUFMANUFACTURING SQUARE BOTTOM PAPER BAG$.

A umioi filed June 19, 1900.

(No Model.) 2 Sheets- Sha i: '2'.

Jhventor:

m: NORRIS PETERS cu, moroumo" WASHINGTON. n. c

WILLIAM A. LORENZ, OFIIARTFORD, CONNECTICUT, ASSTGNOR TO THE UNION PAPER BAG MACHINE COMPANY, OF PHILADELPHIA, PENN- SYLVANIA.

ART CF MANUFACTURING SQUARE-BOTTOM PAPER BAGS.

SPECIFICATION forming part of Letters Patent No. 668,198, dated February 19, 1901. Application filed June 19, 1900. Serial No. 20,824. (No model.)

1'0 Ltbt whmn it may concern:

Be it known that 1, WILLIAM A. LORENZ, a citizen of the United States, residing at Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in the Art of Manufacturing Square-Bottom Paper Bags, of which the following is a full, clear, and exact specification.

This invention is an improved process of forming the diamond fold in a bellows-sided or tucked tube, this process being adapted for use in connection with any of several wellknown methods of forming the tubular blank and of subsequently pasting and folding the flaps of the diamond to complete the bag.

By this improved process the blank is manipulated in such a manner that the so-called inside triangular folds may be easily and quickly formed without subjecting the material to any undue strain which tends to wrinkle and break the surface thereof, and thus impair the strength of the bag-bottom or entirely spoil the product.

My improved process consists in partially distending the tube substantially at the defining line, forming the inside triangular folds, and substantially completing the diamond while maintaining the tube inits distended condition.

This improved process includes the relief of the tensionupon the flap-forming portions of the blank while the tube is thus distended and during the period of opening the tuck sides to form the inside triangular folds, so that the resisting strains to which the material would otherwise be subjected at that Fig. 2 illustrates the blank after its diamondforming end has been opened sufficiently to straighten out the bottoms of the tucked sides.

Fig. 3 represents the end opened until the tucked sides have been spread between the tuck-points practically to form straight-line folds, which will constitute the sides of the diamond later on, the inside triangular folds being well developed at this time. Fig. 3 is a diagram illustrating the effect of maintaining the tube partially distended at the bottom-defining line as compared with the result obtained when said blank is in a collapsed condition. Fig. 4 shows the open end while assuming the diamond form, tension having been applied on the front-flap end and the tucked sides now being fully straightened out between the tuck-points. Fig. 5 illustrates the diamond fully developed and the blanks collapsed; and Fig. 6 shows a complete bag, the flaps of the diamond having been folded over.

The blank 10 is shown having tucked or bellows sides 11, which are partially distended substantially at the defining-line a b in Fig. 1, upon which the lower end of the upper ply of the blank is to be turned back, thus opening the end of the blank.

The instrumentalities ordinarily employed for opening the bag-bottom and forming the diamond fold usually engage the blank at the tuck-points 14 14 and 1515,which determine the sides 16 16 of what subsequently forms the bottom of the bag, these points being gradually separated, as shown in Figs. 2 and 3, so as to open the tucked sides, and thus form the inwardly-extending triangular folds. Those portions of the tucked sides lying beyond the sides 16 16 and comprising the surfaces between these sides and the edges 17 17 are turned inward and subsequently flattened down.

By referring to Fig. 2 it will be seen. that the end of the blank has been opened out by partially folding the upper flat side backward and until the edges of the tuck sides have been distended substantially to form straight side edges 17. By increasing the distance between the points 14 15 and 14 15 the tuck-bottoms 18 are gradually pulled out or straightened, so that the end of the tube will at first present a box-like appearance, as shown in Fig. 3, and then as the edges 16 aptoo also be depressed, so as to completely flatten.

the diamond. The advantages gained by thus relieving the front flap 19 and then depressing it,while at the same time maintaining the distention of the tucks 11, are considerable and permit of much greater speed being attained in the manufacture of paper bags. Until or nearly up to that time when the blank reaches the condition shown in Fig. 4 the side tucks 11 are maintained in their distended condition, and when the diamond is substantially defined said tucks 11 may be flattened to the condition of Fig. 5. This flattening of the side tucks may be effected simultaneously with or just before or after the flattening of the diamond to the condition shown in Fig. 5, according to the nature of the means employed.

As above stated, my present invention includes as one of its features a partial disten-- the sides 16 (see Fig. 3) more readily and quickly than it can be done when the bellows sides of the tube are not distended. Consequently my invention not only obviates the liability of wrinkling the material during the period of folding the bottoms 18'outward to develop the inwardly-extending folds, but, furthermore, on account of the partially-distended condition of the tube sides, the tuckbottoms 18 are already spread to some extent, even before the bottom-folding operation begins. Therefore it follows that less angular movement of the tuck-holders is required to spread out the trucks, the different conditions being clearly illustrated in Fig. 3. In order to unfold the tucks to an amount equal to the distance between the points 14 15, the movement of the point 14, as represented by the angle 14 a b, is considerably less than that represented by the angle 14 a b. In this connection itwill of course be understood that line 14 15 14 15, and 14 a 14 the material; but in order to gain the best results, both as to rapidityof manufacture and excellence of the product, I release the tension on the frontflap 19, in addition to distending the side tucks 11.

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. The process of forming adiamond fold in bellows-sided tubing, which consists in partially'distending the tube substantially at the defining-line; forming the inside triangular folds; and substantially completing the diamond while maintaining the tube in its distended condition.

2. The process of forming a diamond foldin bellows-sided tubing, which consists in partially distending the tube substantially at the defining-line; forming the inside triangular folds; and simultaneously therewith relieving the front-flap end while maintaining the tube in its distended condition, and then completing the diamond.

3. The process of forming a diamond fold in bellows-sided tubing, which consists in partially distending the tube substantially at the defining-line; forming the inside triangular folds; and simultaneouslytherewith relieving the front-flap end and subsequentlydepressing the same; While maintaining the tube in its distended condition.

4. The method of forming a diamond on a tuck-sided paper-bag blank, which comprises a partial separation of the Hat sides of the blank substantially at the defining-line; forming the inside triangular folds; and simultaneously therewith relieving thefront-flap end; and bringing together the separated sides of the blank.

5. The method of forming a diamond on a bellows-sided paper-bag blank,whieh consists of separating the fiat sides of the blank substantially at the defining-line; forming the inside triangular folds while the flap portions of the blank are in an unconfined condition; depressing the front-flap end; and flattening the rear-flap end.

6. The method of forming a diamond on a bellows-sided paper-bag blank,which consists 

